Objective. It is necessary to recycle the waste from fish processing and to evaluate its environmental impact in order to improve the sustainable marine products industry. Thus, we evaluated greenhouse gas (GHG) emissions, one of the environmental impacts, of recycling the waste from fish processing from the composting to the end-use steps. We evaluated the process of conventional composting, the production of fish-meal fertilizer, disposal and acidulocomposting that is a novel eco-friendly composting system.
Results and Discussion. In our evaluations, it was determined that the acidulocomposting process needs larger amounts of energy for heating the fermentation system than normal composting. The amount of energy required in acidulocomposting is almost same as that required in the manufacture of fish-meal fertilizer. The ammonia volatilization and CO2 emission in the acidolocomposting process are much lower than those in conventional composting. The proportion of GHG emissions from transportation and spraying to the recycling processes were low in all cases. The acidulocompost has much higher nitrogen content than the conventional compost because of low ammonia volatilization. Therefore, it can be used across larger areas than conventional compost from an equivalent amount of waste from fish processing. In addition, the GHG emission from the case of disposal is the largest, compared to the rest.
Conclusions. Acidulocomposting needs large amounts of energy for heating the fermentation system but has low GHG emissions from composting. Moreover, acidulocompost has large nitrogen content. Acidulocomposting may be suitable for recycling the waste from the sustainable marine products industry.
